eval{
     local $SIG{ALRM} = sub {die "alarm\n"};
     alarm $timeout;
     $cpid = open3("<&STDIN", ">&STDOUT", ">&STDERR", '-');

     if (!$cpid) { # Child
         setpgrp(0,0);
         exec(@ARGV)
             or die "exec: $!";
     }

     waitpid($cpid, 0);
     alarm 0;
};